555 "Happy Birthday" electronic candle circuit diagram

As shown in the figure, the circuit consists of four parts: light-controlled electronic switch, timing circuit, voice circuit and audio circuit. Used to congratulate birthdays or celebrations. Music is played along with the lighting or blowing out of birthday candles, creating a strong birthday atmosphere.

The optical switch is composed of optical fiber, photosensitive tube, IC1, etc. When the birthday candle is lit, the light beam transmitted from the optical fiber reduces the inter-electrode resistance of the photosensitive transistor 3DU3 to less than tens of kiloohms, 555 starts to vibrate, J1 is attracted, J1-1 is disconnected, and J1-2 is closed. Open the circulation path.

The timing circuit is composed of IC2, IC3, R2, RP2, C3, R4, RP3, C5, etc. Timing time td=1.1(R+RP)C. Adjust RP2 so that the delay of IC2 is td1=1.1 (R2+RP2) C3, about 5 to 6 seconds, so that J2 is attracted and triggers IC4, so that the audio circuit outputs just two English sentences "Happy Birt hd ay". As soon as the temporary stable width of IC2 ends, the monostable state composed of IC3, R4, RP3, and C6 is triggered to set IC3. The delay pulse width is td2=1.1 (R4+RP3) C6, about 10 to 15 seconds. During the pull-in period of J3, IC5 plays the electronic music "Happy Birthday to You". J3 is released, triggering IC2 again, and this cycle continues until the birthday candles are extinguished and the voice and music stop. IC4 uses CIC5607 voice IC, which stores the congratulatory message "Happy Birt hd ay". IC5 uses CW9310, which stores the music "Happy Birthday to You".

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